Roofing felt



Patented Nov. 22, 1927.

UNITED STATES PATENT OFFICE.

ARLIE WILLIAM SCHORGER, OF MADISON, WISCONSIN, ASSIGNOR, BY MESIN'E ASSIGN- MENTS, TO 0. I. PORATION OF DELAWARE.

BURGESS LABORA'IOIRIES,v INQ, OF DOVER, DELAWARE, A COR-- ROOFING FELT.

No Drawing. Application filed December 20, 1924, Serial No. 757,297. 7 Renewed October 1, 1927.

Manufacturers of asphalt shingles utilize each year an enormous tonnage of felt. The felt is saturated with asphaltic material to serve as the body of the shingle, it being customary to surface one face of the saturated felt with a bituminous material having a high melt point and serving as a binder for slate or other mineral or metal particles which act as the weathering face of the shingle. Such felt must be of. considerable strength, for in the ordinary operation of shingle manufacture it is drawn at relatively high speed through-a long bath of the hot asphalt. ing through the bath seriously interrupts the manufacturing operation, for the steps of drying on the looper and the subsequent steps of surfacing with bitumen, sprinkling with slate, and cutting into shingles, are all timed to accommodate continuous passage of the felt through the plant. Any interruption due to breakage of the felt not only shuts down the entire saturating machine and its adjuncts, but is likely to result in considerable loss of material. To avoid these inconveniences, a relatively large percentage of long fibred stock is used in the manufacture of the felt. Clean cotton rags, woolen cloth, waste wool, and the like are relied on to give the necessary tensile strength to the finished felt, even though it may contain some short-fibred stock, such as can be had by beating .up old newspapers, and similar semiwaste products.

It is the object of the present invention to lessen the cost of felt suitable for use in the manufacture of asphalt shingles by making this felt, in part at least, out of'a component of discarded automobile tire casings. Such casings consist, in large measure, of rubber interspersed with cotton fabric. High grade cotton is used for this purpose, and I have found a way of separating it from the rubber without shortening the fibres unduly. The long-fibred stock of high quality thus obtained, with such rubbery components ascling to the fibres, is, I have found, a very excellent material for use in place of the cotton and wool rags heretofore utilized so exltensively in the manufacture of roofing fe ts.

The process whereby the desired end is attained may consist of cutting the tire casings into strips about one-half inch width,

Any tearing of the felt while pass-- and then feeding them into a shredder or disc mill of one of the types now standard in the paper making industry for shredding cooked wood pulp, or chipped wood. The shredding operation, whichever machine is used, serves to break up the rubber into small particles, and in large measure serves to free the cotton fibres from the rubber. Air separation can be used for freeing the mass from the cotton fibres. The fibres so obtained are relatively long and strong, having originally been of very excellent qualit and having been well protected, by the rub ber againstrot and similar attack. Fibres so obtained will ordinarily be accompanied by a certain amount of rubber, because of the previous intimate contact and adhesion between the fabric and the rubber in the tire. This, however, is not a disadvantage, and in my opinion, is a very considerable advantage, when the cotton fibre is to be used in the manufacture of roofing, for this rubber, which may be conceived of as somewhat in the nature of a film on the shredded fibres,

acts as a flux to facilitate the subsequent impregnation with asphalt ofa felt sheet wherein these cotton fibres are an ingredient. To incorporate this cotton in the felt, it

is only necessary to' substitute the cotton fibres for an equivalent amount of cotton rags, wool rags, shoddy, and the like, when the raw material is charged into the beaters at the felt plant.

The proportions 1n which cotton fibres of old tire casings shall be used in the roofing felt will, in large measure, be governed by commercial considerations, but the greater the percenta e of cotton fibre, the stronger will be the elt. Conversely, for an equal strength of felt, a considerably larger ercentage of old newspapers and short bre stock can be charged into the heaters.

The various operations of beating, mixing, felting and drying may be the same as those ordinarily employed in making roofing felt. When such a felt is utilized at a roofing plant, its good qualities quickly become apparent. Not only is it strong and tough, per unit of cost, but the hot asphalt through which it is rapidly passed penetrates quickly through the sheet and gives the desired uniform impregnation, that action being no doubt facilitated by the resence on the fibres of some residue of ru ber from the original tires, that rubber acting much as a flux to bring the asphaltum quick- 1y into intimate contact with the fibres and assisting perhaps also in the penetration of the asphalt into the inner portions of the felt; Such rubber as may remain in the finished sheet-roofing or shingle is not a detriment therein, but on the contrary, is advantageous, particularly because of its intimate contact with and protective action on the long and strong cotton fibres by which the shorter fibres and loading materials are held in place as a coherent sheet.

At the present time old tire casings or shoes have no market value and ordinarily are burned at the garages after the cease to be of value on automobiles. During the war when the price of raw rubber was high a certain amount of work was done on reclaimin old tires for their rubber content, but at t e present normal price of raw rubber, there is, I believe, no commercial demand for old tire casin s for that purpose.

In a companion app ication, Serial No. 757,296 filed December 20, 1924:, I have described and claimed a process of making a veneer core out of the rubber content of old tire casings, and when that is done, or when the rubber content is used in any similar manner, the cotton fibre content is in the nature of a by-product. It is an object of the present invention to utilize that by.-

product, and in a manner and to' an extent that will prevent what is now a large economic waste I claim:

1. A roofing felt comprising an a preciable quantity of cotton fibres recovere from old tire casings,-and having a small quantity of rubber admixed therewith substantially as described.

2. An asphalt roofing containing cotton fibres with such quantity of rubber as normally will be associated with the fibres when they areobtained from old tire casings by shredding and air separation, substantially as described.

3. The method which consists in shredding old tire casings to liberate the fibres of the tire fabric, subjecting the shredded material to an air blast to imperfectly separate the cotton from the rubber, making a roof ing felt wherein the cotton so obtained is an essential in edient, and'subsequently saturating said elt with asphaltic material, substantially as described.

4. In the impregnation of a roofing felt with asphaltic material the step which consists in using in the felt stock an appreciable quantity of cotton fibres recovered from old tire casings and having a small quantity of rubber admixed therewith.

In testimony whereof I aflix my signature.

ARLIE WILLIAM SOHORGER. 

